Published in Agron J 99:1579-1586 (2007)
DOI: 10.2134/agronj2006.0194
© 2007 American Society of Agronomy
677 S. Segoe Rd., Madison, WI 53711 USA
Forages
Summer–Fall Seeding Dates for Six Cool-Season Grasses in the Midwest United States
D. J. Undersandera,* and
L. J. Greubb
a Agronomy Dep., Univ. of Wisconsin, 1575 Linden Dr., Madison, WI 53717
b Plant and Earth Science Dep., Univ. of Wisconsin-River Falls, River Falls, WI 54022
* Corresponding author (djunders{at}wisc.edu)
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ABSTRACT
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The effect of late summer (fall) planting date for cool-season grasses in the upper Midwest is not well understood. Objectives of this research were to determine optimum planting dates of late-summer/fall seedings in different environments for several cool-season grass species and to gain information on tiller density and tillers plant–1 relative to dry matter yield. Late-summer/fall seedings of six forage grasses were made approximately every 2 to 3 wk in 1995, 1996, and 1997 at three sites in Wisconsin. Species included orchardgrass (Dactylis glomerata L.), smooth bromegrass (Bromus inermis Leyss.), timothy (Phleum pretense L.), reed canary grass (Phalaris arundinacea L.), perennial ryegrass (Lolium perenne L.), creeping foxtail (Alopecurus arundinaceus Poir.), and tall fescue (Festuca arundinacea Schreb.). Yield was taken the next spring and plants destructively sampled for plant and tiller counts. Seedings made by mid- to late-September produced stands having visible plants by killing frost at all locations except for 1 yr at River Falls. Seedings after mid-September generally did not produce visible plants until spring, if at all. Many of these seedings failed to produce a stand the next year. Earlier seeding dates usually had more tillers m–2, more tillers plant–1, and higher dry matter yield the following season with first-cut maximums ranging from 3.6 to 6.7 Mg ha–1. Perennial ryegrass, smooth bromegrass, timothy, reed canarygrass and/or tall fescue, often were among the highest yielding species at the earlier seeding dates. At later late summer seeding dates, reed canarygrass, tall fescue, and creeping foxtail usually had low dry matter yield the next year.
Summer–Fall Seeding Dates for Six Cool-Season Grasses in the Midwest United States
D. J. Undersandera,* and
L. J. Greubb
a Agronomy Dep., Univ. of Wisconsin, 1575 Linden Dr., Madison, WI 53717
b Plant and Earth Science Dep., Univ. of Wisconsin-River Falls, River Falls, WI 54022
* Corresponding author (djunders{at}wisc.edu)
Received for publication July 3, 2006.
The effect of late summer (fall) planting date for cool-season grasses in the upper Midwest is not well understood. Objectives of this research were to determine optimum planting dates of late-summer/fall seedings in different environments for several cool-season grass species and to gain information on tiller density and tillers plant–1 relative to dry matter yield. Late-summer/fall seedings of six forage grasses were made approximately every 2 to 3 wk in 1995, 1996, and 1997 at three sites in Wisconsin. Species included orchardgrass (Dactylis glomerata L.), smooth bromegrass (Bromus inermis Leyss.), timothy (Phleum pretense L.), reed canary grass (Phalaris arundinacea L.), perennial ryegrass (Lolium perenne L.), creeping foxtail (Alopecurus arundinaceus Poir.), and tall fescue (Festuca arundinacea Schreb.). Yield was taken the next spring and plants destructively sampled for plant and tiller counts. Seedings made by mid- to late-September produced stands having visible plants by killing frost at all locations except for 1 yr at River Falls. Seedings after mid-September generally did not produce visible plants until spring, if at all. Many of these seedings failed to produce a stand the next year. Earlier seeding dates usually had more tillers m–2, more tillers plant–1, and higher dry matter yield the following season with first-cut maximums ranging from 3.6 to 6.7 Mg ha–1. Perennial ryegrass, smooth bromegrass, timothy, reed canarygrass and/or tall fescue, often were among the highest yielding species at the earlier seeding dates. At later late summer seeding dates, reed canarygrass, tall fescue, and creeping foxtail usually had low dry matter yield the next year.
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INTRODUCTION
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COOL-SEASON GRASSES are an integral part of forage production in northern states. Grasses, when properly managed either alone or in mixture with legumes, can provide quality forage for beef cows (Bos taurus), young stock, dry cows, ewes (Ovis aries), horses (Equus caballus) (Moser and Hoveland, 1996) and dairy cows (Cherney and Cherney, 1999). Grasses tend to improve yield and stability in pasture environments when mixed with legumes (Fales et al., 1996). In addition, grasses have reduced bloat hazard for grazing ruminants in grass/legume mixtures (Essig, 1985). Grass stands also provide excellent erosion protection on sloping land and offer cover, nesting sites, and food for grassland bird species (Paine et al., 1996).
Certain types of grass species such as winter wheat (Triticum aestivum L.), triticale (x Tritiosecale Wittmack), and turf grasses are routinely seeded in the fall, especially in September, in northern climates while forage grasses have generally been seeded in the spring. There are two common approaches to fall seeding: (i) seeding early enough to allow emergence and sufficient development to survive the winter or (ii) dormant seedings where the seed does not germinate until the following spring (Alberta Agriculture, Food, and Rural Development, 2003).
Winter wheat stand survival and subsequent yields were reduced up to 60% as seeding was delayed from early September to late October in Saskatchewan (McLeod et al., 1992). Survival of winter barley in Nebraska was reduced 15% by delaying seeding until late September (Nelson, 1993). In contrast, Kilcher (1961) reported improved stands from later seedings of several native grasses over the period early September to early November in Saskatchewan. White and Horner (1943) reported greatly improved winter survival of unemerged and early stage seedling grasses when fall-seeded into stubble rather than fallow seedbeds.
Late summer and early fall seedings are recommended for most cool-season turfgrass species because of favorable temperature and moisture environments and less potential from weed competition (Beard, 1973; Schmidt and Blaser, 1969; Turgeon, 1980). Late-summer seeding is also recommended for cool-season forage grasses to take advantage of cooler fall temperatures and usually favorable soil moisture conditions (Buxton and Wedin, 1970; Cosgrove and Collins, 2003). However, little work has been done with cool-season forage grasses to determine how far into the fall period such species can be established successfully, and to determine if there is an optimum seeding window in northern states. Late-summer to fall seeding date trials including three grass species in Pennsylvania reported the highest subsequent year dry matter yield for orchardgrass seeded during August but found a nearly linear decline to zero yield as seeding date was delayed into September or October depending on location (Hall, 1995). Perennial ryegrass yields increased as planting was delayed from early August to early September and then decreased rapidly with later planting dates, especially in central Pennsylvania. For reed canarygrass however, there was an immediate linear decline in following year dry matter yield as seeding date was delayed from early August to mid-September or late October in central or southern Pennsylvania respectively.
Our objectives were to determine: (i) likelihood of successful stand establishment with late-summer and fall seedings in different environments; (ii) species differences in optimum seeding date; and (iii) differences among species in tiller density and tillers plant–1 relative to dry matter yield.
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MATERIALS AND METHODS
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The experiment was conducted over a 3-yr period with seedings made in 1995, 1996, and 1997. Seedings were made in western Wisconsin at River Falls (RF) (44°51' N, 92°37' W) on a Nickin silt loam (fine-loamy over sandy or sandy-skeletal, mixed, over siliceous, active, frigid Typic Argiudoll) and on a Sparta loamy sand (sandy, mixed, mesic Entic Hapludoll); in south-central Wisconsin at Arlington (Arl) (43°18' N, 89°21' W) on a Plano silt loam (fine-silty, mixed, mesic Typic Argiudoll); and in southwestern Wisconsin at Lancaster (Lan) (42°50' N, 90°47' W) on a Rozetta silt loam (fine-silty, mixed superactive mesic Typic Hapludalf). Seeding dates were every 2 to 3 wk from late July/early August to late October/early November (Table 1
).
Six grass species were arranged in blocks by seeding dates (Table 1) with four replicates. Species seeded were: orchardgrass (cv. Dawn), smooth bromegrass (cv. Barton in 1995 and 1996 and Big Ton in 1997), timothy (cv. Climax), reed canarygrass (cv. Palaton), perennial ryegrass (cv. Abisque), and creeping foxtail (cv. Garrison) or tall fescue (cv. Kentucky 31).
Plots of all sites were tilled to loosen soil and remove competition/residue from the previous crop. At Arlington and Lancaster plots were seeded with a Wintersteiger (Wintersteiger, Reid, Austria) small-plot drill. At River Falls, seedings made with a Brillion plot seeder (Brillion Iron Works, Inc., Brillion, WI) in 1995 and 1996 except in 1997 when the existing stand was killed with glyphosate, the residue removed and plots seeded with a Truax no-till drill (Truax Co., Inc., Minneapolis, MN). Seed weight was determined by weight of 500 counted seeds for each species. Seeding rate was determined by weight of seed dropped through seeder openings (Table 2
). Seeding year weeds were controlled by clipping, if necessary, and second year early season broad-leaved weeds were controlled with an application of 2, 4-D amine (dimethylamine salt of 2,4-Dichlorophenoxyacetic acid) where needed.
The number of tillers and plants were determined on surviving stands the spring following seeding by digging plants while in the vegetative to early elongation growth stages (V1–E2 per Moore et al., 1991) from a randomly selected 0.62 by 1 m quadrate area in each plot and then counting plants and tillers. Dry matter yields were taken on successfully established stands the year following establishment except at Arlington and Lancaster in 1996 or where a seeding failed. At River Falls, harvesting of first cuttings in 1996 and 1998 were staggered by seeding date to allow all or most of the species within a seeding date to reach the early to mid-heading maturity stages (R0–R3 per Moore et al., 1991). At Arlington and Lancaster, the stands of all seeding dates within each year were harvested at the same time. Approximately 400-g subsamples of the chopped forage were taken from each plot and dried at 57°C for dry matter determination.
The experimental design was a randomized complete block with a split-split-plot arrangement of treatments where sites were whole plots, seeding dates were the subplots and species were subsubplots. Data was analyzed with PROC MIXED (SAS Institute Inc., Cary, NC); a type III analysis was used to adjust for unequal sample sizes. Locations were considered a fixed effect and other factors random. Statistical significance was accepted as P < 0.05.
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RESULTS AND DISCUSSION
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Stand
Weather conditions at River Falls (northernmost site) in all years were such that the ground began to freeze within 3 to 14 d after the last seeding date and generally remained frozen and snow covered until spring (Fig. 1
). Seedings made by mid- to late-September generally produced visible seedling plants of all species by soil freeze-up. Seedings after mid-September usually produced no visible plants until spring. At Arlington and Lancaster, seedings generally produced some visible plants in the fall from all seeding dates, except for occasional dry periods. Winters tend to occur with less consistent snow cover at the two southern sites. Conditions during this study were such that periodic thawing occurred during most winters that severely damaged some stands. The periodic snow loss resulted in surface thawing and greenup of some perennial species once or twice during winter which were damaged when freezing occurred again.
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Fig. 1. Weekly high and low temperature and rainfall during the late summer/fall seeding periods at Arlington, Lancaster, and River Fall, WI.
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The 1996–1997 seedings at River Falls generally failed due to dry soil conditions at time of seeding; variable winter snow cover; and, especially, a sudden, severe cold snap with temperatures near –17°C in April 1997 after winter dormancy had been broken. At Arlington, in the same year, all stands were lost after the second seeding date when seedings on most dates germinated but did not survive the winter.
While all seeding dates produced a stand at some location/year combination, only the August and early September seeding dates produced generally acceptable stands the next spring with some degree of consistency (Fig. 2
). There were some interactions between seeding date and species that will be discussed later in this paper.
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Fig. 2. Plant density of several grasses in spring after fall seeding at Arlington (Arl), Lancaster (Lan), and River Falls (RF), WI, 1995 to 1998. Date numbers on x axis refer to Table 1. Standard error of mean = 16.6.
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Dormant seedings were attempted each year at River Falls and in the second and third years of the study at the other two sites (last seeding date, Table 1). The concept of dormant seeding is to place seed in (or on) the soil that would not germinate until the next spring. This has proven itself an acceptible seeding method for warm-season grasses in some states (Moser and Vogel, 1995) and cool-season grasses in the northern United States and Canada (Meyer, 1999; Alberta Agriculture, 2005; and Manitoba Agriculture, Food and Rural Initiatives, 2002), though spring seeding is generally recommended due to greater likelihood of stand establishment success. Successful dormant seeding is contingent on winter freeze-up and snow cover following relatively soon after seeding and remaining throughout the winter. Lack of snow cover causes the soil surface to warm from sunlight and some grasses may germinate and then die from freezing. Additionally, birds and other vertebrates may consume the seed. In this study, only one seeding (River Falls in 1995) out of five dormant seedings (fifth seeding date at River Falls all 3 yr and 1996 seedings at Lancaster and Arlington) produced any stand. Therefore dormant seeding does not appear to be a useful practice for this region.
Data from River Falls and Lancaster indicate that at least some seedlings in the pre-emergence (G2) to very early emergence (G5) growth stages at freeze-up apparently can survive the winter. This also was reported by Hoveland et al. (1974) and White and Horner (1943).
Tiller Production
Tillers per plant in the spring following seeding varied greatly among species within a seeding date and year (Fig. 3
). Ryegrass tended to have the largest number of tillers per plant (P < 0.01) while other species tended to be more similar and averaged much fewer tillers per plant.
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Fig. 3. Tillers per plant of several grasses in spring after fall seeding at Arlington (Arl), Lancaster (Lan), and River Falls (RF), WI, 1995 to 1998. Date numbers on x axis refer to Table 1. Standard error of mean = 0.66.
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Delayed seeding date in the fall tended to greatly reduce the number of tillers per plant for slow establishing species such as smooth bromegrass and reed canarygrass. Tillers per plant also declined for tall fescue as seeding date was delayed in the fall. The influence of fall seeding date was much less for orchardgrass, timothy, perennial ryegrass and creeping foxtail. Tillers of these species are formed in the fall and, for ryegrass, both in fall and over winter (Korte, 1986). While tillering is known to be influenced by environment, the relationship is complex reflecting growth rate and associated factors such as temperature, daylength, and drought stress.
Tillers per plant were much less affected fall seeding date than plant density. In several environments, tillers per plant varied only slightly while plant density declined significantly (P < 0.05) with seeding date. Tillers per plant were positively correlated (P < 0.05) with plant density (by comparing Fig. 2 and 3). We believe this is due to the generally higher plant densities at earlier seeding dates which then had warmer temperatures after emergence in the fall. Increased tillering with higher temperatures was reported by Kirby and Perry (1987).
Tillering was significantly related to yield overall but had low correlations with yield for individual species (Table 3
). This lack of relationship is often found as yield increases in forages grasses, indicating that weight per tiller was the major yield component. An extreme example is the first seeding date of tall fescue in early September at Lancaster where 584 plants per square meter with an average of 7.2 tillers per plant resulted in nearly 4,646 tillers m–2 and only 0.3 Mg ha–1 yield. More than twice the tiller density resulted in less yield than the following planting date. It is apparent that yield per tiller was generally more important as reported by Zarrough et al. (1984). Biddescombe et al. (1969) found that, at least for orchardgrass, tiller number was the main component in the yield of young plants but growth per tiller became more important in older plants. Lower plant populations often were offset by increased tillers per plant for reed canarygrass and creeping fescue.
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Table 3. Relationship of plant density (plants m–2 and tillers m–2) to yield (dry matter) of several grasses in spring after fall seeding averaged over locations in Wisconsin, 1996 to 1998. Values regressed are each plot yield for each species at each seeding date and location.
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Yield
Spring yield generally declined as seeding was delayed after mid-August the previous late summer and early fall (Fig. 4
). However, the rate and timing of change varied with species and environment. Reed canarygrass tended to show greater yield and stand reductions (P < 0.05) with the later seeding dates (mid-September) than other species. This is not surprising due to the slow establishment of this species. Timothy tended to be the most variable with regard to seeding date and next year yield. Timothy was most consistent at the most northern site. This probably relates to the high winter survival ability of timothy because of its tolerance to freezing stress and ice encasement (Andrews and Gudliefsson, 1983; Berg et al., 1996). Stands appeared to recover during the year after establishment as yield in the second year after seeding showed little or no relationship with seeding date or with dry matter yield of the six grasses in the second year after establishment (data not presented).
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Fig. 4. Yield (dry matter) of several grasses in spring after fall seeding at Arlington (Arl), Lancaster (Lan), and River Falls (RF), WI, 1995 to 1998. Date numbers on x axis refer to Table 1. Standard error of mean = 0.44.
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Orchardgrass, timothy, and reed canarygrass showed some increased yield from the last seeding date compared to other late September and October seeding dates due to dormant seeding success at some sites. The higher success with these species may relate to the higher seeding rate of orchardgrass and timothy and to the smaller seed size of timothy and reed canarygrass so that vertebrates consumed less.
Yield reduction in the year following seeding is a significant economic consideration. Since over half of production costs are fixed (for example, land charges, taxes, depreciation on facilities) and even harvesting costs vary little with yield, the major factor affecting cost per ton of production is yield (Barnett, 2005). In all cases, yield was reduced by more than 1 Mg ha–1 over ranges of plant densities that were acceptable for keeping the stand. Thus, not only is the risk of stand failure increased as later summer seeding is delayed, but yield of the grass the next year is greatly reduced.
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CONCLUSIONS
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Seeding of cool-season grasses at Arlington was successful when completed in August to mid-September but failed for all later seeding dates. Results were generally similar at Lancaster with very limited success for seedings in late September, October, or November. At River Falls, stands ranging from very successful to acceptable for most species were achieved in 2 out of 3 yr for all seeding dates through late October. Results of this study indicate that August and early September seedings of these six cool-seasons grasses generally produced the highest subsequent year tiller densities and first cutting dry matter yield the year after seeding at all three locations in WI. Those species that established faster could generally be planted slightly later than other species. Tiller density and dry matter yield did not always decrease in a linear fashion with delayed planting date, especially at River Falls.
Only one dormant seeding out of five produced any stands. Therefore dormant seeding does not appear to be a useful practice for this region. Whether failure was due to seed loss to vertibrates or germination and death is unknown. Further research is needed to determine if germination inhibitors may increase success of this practice.
Dry matter yields taken on stands seeded 2 yr prior suggest that, if plants, seedlings, or seeds survive the winter, any differences in first-year tiller densities and dry matter yield may have little or no effect on second and subsequent year yield potential.
The risk with late-summer and fall seedings in the Midwest, however, was well exemplified by the complete failure for all seeding dates at River Falls in 1996 to 1997. Late summer and fall seedings should only be considered when good soil moisture conditions exist.
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REFERENCES
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- Alberta Agriculture, Food, and Rural Development. 2003. Late fall or dormant seeding frequently asked questions. Available at www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/faq7329?opendocument (modified 1 Sept. 2006; accessed October 2006; verified 31 Aug. 2007). Gov. of Alberta, Calgary.
- Alberta Agriculture, Food, and Rural Development. 2005. Perennial forage establishment in Alberta. Available at www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/agdex9682 (accessed July 2006, October 2006; verified 31 Aug. 2007). Gov. of Alberta, Calgary.
- Andrews, C.J., and B.E. Gudliefsson. 1983. A comparison of cold hardiness and ice encasement tolerance of timothy grass and winter wheat. Can. J. Plant Sci. 63:429–435.
- Barnett, K.H. 2005. Economics of alfalfa and corn silage rotations. Available at www.uwex.edu/ces/crops/uwforage/Alf-CornSil-RotationCOP.pdf (accessed October 2006, verified 31 Aug. 2007). Univ. of Wisconsin, Madison.
- Beard, J.B. 1973. Turfgrass: Science and culture. Prentice Hall, Englewood Cliffs, NJ.
- Berg, C.C., A.R. McElroy, and H.T. Kunelius. 1996. Timothy. p. 643–664. In L.E. Moser et al. (ed.) Cool-season forage grasses. Monogr. 34. ASA, CSSA, and SSSA, Madison, WI.
- Biddescombe, E.F., P. Brone, and C.A. Neal-Smith. 1969. Relative winter performance of cocksfoot lines in first and fourth year swards. Aust. J. Exp. Agric. Anim. Husb. 9:299–303.
- Buxton, D.R., and W.F. Wedin. 1970. Establishment of perennial forages. I. Subsequent yields. Agron. J. 62:93–97.[Abstract/Free Full Text]
- Cherney, J.H., and D.J.R. Cherney. 1999. Grass for dairy cattle. Oxford Univ. Press, Cary, NC.
- Cosgrove, D.R., and M. Collins. 2003. Forage establishment. p. 239–261. In R.F. Barnes et al. (ed.) Forages: An introduction to grassland agriculture, Vol. 1. 6th ed. Iowa State Press, Ames.
- Essig, H.W. 1985. Quality and antiquality components. p. 309–325. In N.L. Taylor (ed.) Clover science and technology. Agron. Monogr. 25. ASA, CSSA, and SSSA, Madison, WI.
- Fales, S.L., A.S. Laidlaw, and M.G. Lambert. 1996. Cool-season grass ecosystems. p. 267–296. In L.E. Moser et al. (ed.) Cool-season forage grasses. Agron. Monogr. 34. ASA, CSSA, and SSSA, Madison, WI.
- Hall, M.H. 1995. Plant vigor and yield of perennial cool-season forage crops when summer planting is delayed. J. Prod. Agric. 8:233–238.
- Hoveland, C.S., H.W. Foutch, and G.A. Buchanan. 1974. Response of Phalaris genotypes and other cool-season grasses to temperature. Agron. J. 66:686–690.[Abstract/Free Full Text]
- Kilcher, M.R. 1961. Fall seeding versus spring seeding in the establishment of five grasses and one alfalfa in southern Saskatchewan. J. Range Manage. 14:320–322.
- Kirby, E.J.M., and M.W. Perry. 1987. Leaf emergence rates of wheat in a Mediterranean environment. Aust. J. Agric. Res. 38:455–464.[CrossRef][Web of Science]
- Korte, C.J. 1986. Tillering in Grasslands Nui Perennial ryegrass swards. 2. Seasonal pattern of tillering and are of flowering tillers with two mowing frequencies. N. Z. J. Agric. Res. 29:629–638.
- Manitoba Agriculture, Food and Rural Initiatives. 2002. Forage crops—Forage establishment. Available at www.gov.mb.ca/agriculture/crops/forages/bja03s20.html. (accessed July 2006, October 2006; verified 31 Aug. 2007). Gov. of Manitoba, Winnipeg.
- McLeod, J.G., C.A. Campbell, F.B. Dyck, and C.L. Vera. 1992. Optimum seeding date for winter wheat in southwestern Saskatchewan. Agron. J. 84:86–90.[Abstract/Free Full Text]
- Meyer, D.W. 1999. Forage establishment. R- 563. North Dakota State Univ. Ext. Serv., Fargo.
- Moore, K.J., L.E. Moser, K.P. Vogel, S.S. Waller, B.E. Johnson, and J.F. Peterson. 1991. Describing and quantifying growth stages of perennial forage grasses. Agron. J. 83:1073–1077.[Abstract/Free Full Text]
- Moser, L.E., and C.S. Hoveland. 1996. Cool-season grass overview. p. 1–14. In L.E. Moser et al. (ed.) Cool-season forage grasses. Monogr. 34, ASA, CSSA, and SSSA, Madison, WI.
- Moser, L.E., and K.P. Vogel. 1995. Switchgrass, big bluestem, and indiangrass. p. 409–420. In R.F. Barnes et al. (ed.) Forages: An introduction to grassland agriculture. Vol. 1, 5th ed. Iowa State Press, Ames.
- Nelson, L.A. 1993. Influence of date, depth, and rate of seeding on winter barley survival. J. Prod. Agric. 6:77–79.
- Paine, L.K., T.L. Peterson, D.J. Undersander, K.C. Rineer, G.A. Bartlet, S.A. Temple, D.W. Sample, and R.M. Klemme. 1996. Some ecological and socio-economic considerations for biomass energy crop production. Biomass Bioenergy 10:231–242.[CrossRef][Web of Science]
- Schmidt, R.E., and R.E. Blaser. 1969. Ecology and turf management. p. 217–239. In A.A. Hanson and F.V. Juska (ed.) Turfgrass science. Monogr. 14. ASA, Madison, WI.
- Turgeon, A.J. 1980. Turfgrass management. Reston Publ. Co., Reston, VA.
- White, W.J., and W.H. Horner. 1943. The winter survival of grass and legume plants in fall sown plots. Sci. Agric. 23:399–408.
- Zarrough, K.M., C.J. Nelson, and D.A. Sleper. 1984. Interrelationships between rates of leaf appearance and tillering in selected tall fescue populations. Crop Sci. 24:565–569.[Abstract/Free Full Text]
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ABSTRACT
INTRODUCTION
